Improvements in currently available lithium-ion battery systems (e.g. with regard to energy density, safety, and cost) can improve the suitability of these technologies for use in electric vehicle applications. Typically, a lithium ion battery is composed of a negative electroactive material, a positive electroactive material, an electrolyte, and a separator. In current technology, the working voltage, capacity, and rate capability of lithium-ion batteries are mainly determined by the limited capacity and thermodynamics of the positive electroactive material. Consequently, the development of superior positive electroactive materials is desirable, particularly for demanding electric vehicle applications.
Currently, there are four main types of positive electroactive materials for electric vehicle applications: lithium nickel cobalt oxide, lithium iron phosphate, lithium manganese oxide and lithium nickel manganese cobalt oxide. The characteristics of each material present different advantages and disadvantages to their industrial applications: lithium nickel cobalt aluminum oxide positive electroactive materials can deliver high capacity but generally suffer from significant safety problems; lithium iron phosphate positive electroactive materials are safer and generally offer a long cycle life, but have the lowest energy density; and lithium manganese oxide positive electroactive materials offer high thermal stability but have relatively low capacity and suffer from manganese dissolution. Since the capacity and rate performance of current positive electroactive materials cannot meet the demands of the emerging electric vehicle market, it would be desirable to develop a high-performance positive electroactive material with a high capacity and superior rate capability.